1. Field of the Invention
The present invention relates to a method and apparatus for object detection and ranging, which is used by vehicle backing systems, especially to a technique that incorporates dynamic adjustment of environmental control parameters in the object detection and ranging process, so as to enhance the system accuracy.
2. Description of Related Art
When back-up sensors are installed in ordinary sedans, one of their main concerns is the accuracy in object detection and ranging. Erroneous triggering of back-up sensor alarms is often due to inadequate design of the control circuits rather than environmental interference. Ordinary sensors might react to a stray signal as if it was a signal reflection from a real object, when in fact there is no obstruction in the detecting range.
Since ranging signals are emitted radially, experiments show that roads covered by stones or small rocks often generate a great deal of ground clutter for the sensor. Besides, four-wheel drive vehicles, such as trucks or jeeps, often have spare tires or other hoisting gear mounted at the back of the vehicle, which tend to produce a considerable amount of clutter. Under such circumstances, vehicle back-up sensors often pick up false signals and activate the alarm, but in fact there is no obstruction behind the vehicle. These false alarms from the back-up sensor are quite annoying for vehicle drivers.
These and other problems can be avoided if the back-up sensor incorporates dynamic adjustment of environmental control parameters in the object detection and ranging procedures to filter out unwanted noise, thus enhancing the overall system accuracy.